The Euthyphro is a discussion of piety, and for the ancient Greeks, acting piously is one way of acting virtuously. The Greeks had a strongly developed sense of virtue (arête, or excellence) manifest in its literature and culture in general. Plato and Aristotle would study virtue intensively after Socrates. His own investigations led him to the conclusion that virtue is inseparable from knowledge. Anyone who knows what is right will do the right thing, and bad actions stem from ignorance. This is a very controversial view, as most philosophers have held that desire for the bad frequently overcomes knowledge of the good.
